Run Away Mack Engine locks up.
crete 04-28-2016 comment profile send pm notify

Sooo I fire up my 2000 Mack Telebelt a week ago and it pegs the tach and start billowing black smoke. I tried to stuff the clutch in to get it into gear,key won't shut it off. By the time I tried to get a shirt or something into the air cleaner it locks up. At the Mack dealer now and they confirm the crankshaft seized. Turbo was not the culprit. All off the injectors were replaced about 2 days before it happened. No love from the dealer as they say the injectors are all still good. The next thing they are going to check out today it the ECM and pump. So now I'm looking at 25 or 30k for a new Mack reman. Anyone experience such a thing?

bisley57 04-28-2016 reply profile send pm notify

In the late 70s the diesel engines that ran our boat always had a means of choking the air intake if there was a runaway.A scary thing indeed,although handled properly damage will be minimalized.It is a very good thing you mentioned this old fact where some of these younger operators have never heard such a thing

wannadrag 04-28-2016 reply profile send pm notify

Man that sucks although I have never personally experienced a run away, I did have a good conversation with a buddy about it.

Only way to stop it is to stop the air or the fuel.

A scary thought.

b-alto 04-28-2016 reply profile send pm notify

Wow Terry that sucks! What the heck, the fuel must have stuck wide open? It sure sounds fishy since they just worked on the fuel system. I have never heard of such a thing. Maybe call some mechanics  and ask if they know what happened . That dealer won't thats for sure.

crete 04-29-2016 reply profile send pm notify

Exactly Got a new Mack reman engine coming, but it doesn't include the fuel system. So they have to test the pump and ecu for problems. Phone ringing off the hook and downed equipment. Very frustrating.

b-alto 04-29-2016 reply profile send pm notify

Terry I talked to my mechanic buddy he said it sucked oil from the pan and was running off of oil wildly! He said they must have done something wrong and to call Mack . It sucked the oil out of the crank case and ran dry .

wannadrag 04-29-2016 reply profile send pm notify

b-alto, exactly. I was working on a 7.3 ford that  the turbo housing bolts had backed out, and in talking to my friend he brought up how the engine could run away off of motor oil being ingested by the turbo/engine.


It truly is a viscous cycle. Engine ingests unmetered fuel/oil and takes off (as fast as it can spin) until either fuel or air supply stops.

pudg2 04-29-2016 reply profile send pm notify

I had a old 3208 CAT do this , had to choke the air intake luckily it didn't damage the motor , the problem was in the injector pump.

b-alto 04-29-2016 reply profile send pm notify

He said it probably ran until the engine ran out of oil and seized the crank. My guess is oil getting into the intake through a o ring or leaking head gasket? It shouldn't have spun the crank just from high revs I wouldn't think.

Dipstick 05-01-2016 reply profile send pm notify

I really don't understand why we are havig this discussion in 2016...:-O



b-alto 05-03-2016 reply profile send pm notify

It could have been a faulty turbo. But i don't believe in coincidences.

If this run away oil fed engine syndrome ever happens the only way to stop it is to block off the turbo with something rigid like a board because its pulling a lot of pressure!

crete 05-04-2016 reply profile send pm notify

ruled out the turbo no excessive oil/fuel. Newest brain storm is the pump or the ecu.

b-alto 05-04-2016 reply profile send pm notify

It would have shut off with the key Terry. I would have the engine autopsied . The people that rebuilt the injectors did something wrong.